1. Field of the Invention
This invention relates generally to a condition-responsive switch, and particularly to a switch actuated by the presence of water, or similar liquid, so as to energize an associated alarm circuit, and the like.
2. Description of the Prior Art
There is a definite need for a water-sensitive switch which will detect the presence of a small amount of water on a floor, and the like, and which will actuate an alarm circuit in order to give warning of the water leakage and permit early action to be taken before serious water damage occurs. Such a switch would be particularly useful when placed in remote or seldom visited locations, such as closets, under counter storage spaces, utility rooms, and the like, in which water piping, valving, and storage tanks are located.
U.S. Pat. No. 539,234, issued May 14, 1895 to G. S. Neu, discloses a water alarm switch intended for use in conjunction with conventional automatic fire sprinkler systems in order to give warning of actuation of the associated sprinkler. Further, U.S. Pat. No. 3,787,650, issued Jan. 22, 1974 to W. J. Lewis, discloses a water detecting device which detects the presence of water in fuel lines, and the like. Both of these known water detecting arrangements rely on a water-soluble element which will dissolve in the presence of water, or similar liquid, and cause a spring biased electrical switch element to close in order to actuate an external alarm circuit. U.S. Pat. Nos. 896,874, issued Aug. 25, 1908 to H. Williams, 1,106,151, issued Aug. 4, 1914 to G. H. Matthews, and 1,116,458, issued Nov. 10, 1914 to M. Matos, disclose condition responsive switches of generally similar construction to those referred to above, but being heat responsive as opposed to water responsive. These known condition-responsive switches, however, are not specifically intended, or especially suited, for use when sensing the presence of a small amount, perhaps as little as 1/25th of an inch (approximately one millimeter) of water, and the like, on a floor or similar support surface.